The invention is based on a device for separating liquid from a gas flow.
A device for separating liquid, in particular oil, in which a plurality of parallel-connected cyclones are provided is already known from German Patent Disclosure DE 199 12 271 A1. However, in operating states of an internal combustion engine in which a volumetric flow of blowby gas to be cleaned, coming from a crankcase ventilation system, fluctuates comparatively sharply over time, either individual cyclones or parallel-connected cyclones have a poor separating action. Oil contained in the blowby gas from the crankcase ventilation system, however, must be reliably separated if a high oil loss is to be avoided, since the blowby gas is mixed with an intake flow in an intake tube of the engine, and oil contained in the blowby gas would thus be combusted in the engine. Moreover, oil contained in the blowby gas can also damage components of the engine, such as hot-film manometers, turbochargers, charge air coolers, and the lambda sensor.
From German Patent Disclosure DE 197 00 733 A1, it is known that nonwoven fabrics, knitted wire goods, wire wool, yarns or granulates can be used to separate liquid, especially oil, in a fine separator. Over the course of time, however, these materials become clogged, so that they must be replaced at predetermined intervals.
In German Patent Application 102 47 123, which had not yet been published by the priority date of the present application, a device for separating liquid that has parallel-connected spirals and coils has already been proposed. A high degree of separation with a low pressure loss can be attained only at an optimal operating point and at a predetermined volumetric flow. The volumetric flow of blowby gas is dependent on the operating state and rpm of the engine, on production tolerances between the piston and cylinder of the engine, and on wear between the piston and cylinder. The volumetric flow of blowby gas therefore varies sharply during engine operation. As a result, the device operates only rarely at its optimal operating point, and hence the degree of separation is lower, compared to the optimal operating point.